Heating device



Aug. 11, 1936. O R JORDAN 2,050,332

HEATING DEVICE Filed Feb. 21, 1954 2 Sheets-Sheet 2 WITNESSES: INVENTORW I Richard H Jordan.

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Patented Aug. 11, 1936 UNITED STATS YET FFlCE HEATING DEVICE ofPennsylvania Application February 21, 1934, Serial No. 712,349

6 Claims.

My invention relates to electrical heating devices and it has particularrelation to electric hand driers and other comparable devices whichproduce a stream of heated air for direction against objects which areto be dried.

In order to eliminate the necessity for towels in business office,public, and other washrooms, there have, in recent years, been developedmechanical driers which typically comprise an electric heater throughwhich a motor-driven blower discharges air for direction against thehands and face of a user. All devices of. this character with which I amfamiliar have, however, been subject to certain limitations anddisadvantages, especially when considered for residence installation,and it is to the overcoming of such disadvantages and limitations thatthe present invention is directed.

'One object of my invention is to provide an electrical hand drier whichis compact in design and artistic in appearance.

Another object of my invention is to provide a construction for dryingdevices .of the type under consideration which facilitates an adjustmentof the direction of discharge of. the heated air.

A further object is to protect the heating unit of the drier from damageupon failure of the blower to operate.

Another object of my invention is to improve the startingcharacteristics of driving motors of the single-phase induction type.

A still further object is to protect the drier control switch fromdamage in the event of excess movement of the operating foot treadle.

Another object of my invention is to provide a construction forhand-driers which facilitates a concealment of the floor-fasteningmeans.

An additional object of my invention is to improve the construction ofelectrical heating units adapted for use in hand driers and othercomparable heating devices.

My invention itself, together with additional objects and advantagesthereof, will best be understood through the following description of aspecific embodiment when taken in conjunction with the accompanyingdrawings in which:

Figure 1 is a view in side elevation of the improved hand drier of myinvention, a portion of the exterior casing being cut away to indicatethe internal construction;

Fig. 2 is a view in end elevation of the device of Fig. 1, a portion ofthe exterior casing also being cut away;

Figs. 3, 4 and 5 are section views respectively taken .on lines III-III,IV-IV and V-V of Figs. 1 and 2;

Fig. 6 is a plan view of the improved heating unit which forms a part ofthe drier shown in the preceding figures;

Fig. 7 is a view in side elevation of the heater of Fi 6;

Fig. 8 is a side elevational view of one of. the resistance-wiresupports which forms a part of the heater of Figs. 6 and 7.

Fig. 9 is a view in end elevation of one of the support spacersincorporated in this heater;

Fig. 10 is a view in side elevation of the heaterprotecting centrifugalswitch which is responsive to the speed of the blower shaft;

Fig. 11 is a view in end elevation of the rotatable composite-ringassemblage which forms a part of. the centrifugal switch of Fig. 10;

Fig. 12 is a View in end elevation of the stationary frame and contactcarriage comprised by this switch; and,

Fig. 13 is a simplified or schematic diagram showing one preferredmanner in which the .electrical devices comprised by the improved handdrier of my invention are interconnected with each other forenergization from a power circuit.

Referring to the drawings, and particularly to Figs. 1 and 2 thereof,the hand drier of my invention there shown comprises an air blower Illwhich is supported in an angle-iron frame comprising four uprightmembers l2, suitably braced and interconnected by cross members certainof which are shown at M and It. Underneath the blower it, which may beof. any one of a number of well-known types now commercially available,is mounted an electric motor 20 which drives the blower by means of anendless belt 22 interconnecting a pulley 2! carried by the motor with acooperating pulley 24 attached to one end of the blower shaft H2. Thisparticular arrangement of the blower and its driving motor, when of theform and relative proportions shown, has the advantage of reducing thethickness of the complete drier assemblage and, hence, in the interestof compactness of design, is the one which I prefer to utilize.

In the cylindrical air-discharge passage 28 of the blower is positionedan electrical heating unit, the construction of which is more completelyshown in Figs. 6 to 9, inclusive. In Figs. 1 and 2 only the protrudingtop portion 36 of this heater is represented. Operation of the drier iscontrolled by means of a switch 80, mounted on the angle iron framework. While, as shown, the

.the manner shown.

switch is actuated by means of a foot treadle 83, it will be understoodthat, if desired, other actuating means may be used to effect itsoperation.

Surrounding the draft-producing and airheating equipment just describedis a suitable casing which, as shown, comprises two identical halves 36,preferably constructed of sheet metal, which, as may best be seen by aninspection of Fig. 5, are interconnected by means of. metal spacerstrips 38 and 39. It will be observed that each edge of the spacingstrips 38 and 39 interfits between a flanged portion 48 of the casingmember 36 and a soldered-on portion 39 which completes a groove of theproper dimensions and character. This exterior casing completely coversand hence conceals the draft-producing mechanism and in addition forms,above a partition member to, a pressure chamber or compartment intowhich the heated air is blown. From this chamber the warm air isdischarged for drying.

purposes through a suitable opening in the top thereof.

It is found preferable to completely assemble the exterior casing beforefitting the same down over the blower and driving motor unit to whichthe two casing halves 36 may be secured by means of screws i l which fitinto threaded holes 45 suitably positioned in certain members of theframe of the blower units. To cover the heads of these attaching screwsid, and to otherwise improve the external appearance of the drier, metalstrips 52 are vertically positioned in the manner shown along thecenters of the two sides of the casing, they being. fitted in a notch 53at their lower ends and held at their upper ends by the washer orbearing members a l of the outlet fixture adjuster. To hold the casinghalves together during the assembly operation and to further strengthenthe complete assemblage at the upper portion thereof, cross braces itare provided.

To isolate any vibration which may originate in the hand drier, rubbersupports 86 secured to the feet of the blower mechanism framework in themanner shown are provided to effect a resilient contact with the flooror other surface upon which the drier may be set. These supports 86protrude a short distance below the lower edge of the exterior casing 36and thereby separate it fromdirect contact with the supporting surface.

While any suitable means for effecting the required air-tight partitionbetween the upper and lower compartments of the blower may be uti'lized, I have found that a layer of felt represented at it, the contourof which is such that it intimately contacts the sides of thesurrounding casing, in the manner best indicated by Fig. 5, isexceedingly effective. To secure this layer of felt in place, a thinplate of sheet metal ii may be clamped down over the top of the felt bymeans of screws "13 which secure it to the structural members of theblower supporting framework therebeneath.

In order that air for discharge through the blower into the upper orpressure compartment may be admitted into the space occupied by theblower structure Ml, which draws it through the open spaces in thespoked end bracket l M of the blower, suitable openings HQ may be madein each end of the lower portion of the casing in During operation ofthe drier, the air from the room is drawn in through these openings llD,discharged by the blower ill, through the heating coils (Fig. 5)positioned in the outlet 28 of the blower, into the pressure chamber inthe upper portion of the casing from which it escapes through the outletfixture 42 for direction against the objects to be dried.

The discharge fixture %2 is adjustably mounted to permit the directionof the stream of warm air to be changed by the manipulation of handles58 which protrude from the pressure chamber sides. When, as illustratedin the drawings, the opening occupies the central or mid-position in itsrange of adjustment, the heated air will be discharged in a verticaldirection from the top of the casing,

The discharge fixture l2 comprises a frame 64 which is supported,through a pair of sheet metal strips 8%, from a shaft 5%, to theprotruding ends of which shaft are attached the adjusting handles 58.These supporting strips may be secured to the shaft by any suitablemeans such as the pairs of cooperating nuts 62, and have fixed to theirupper ends, as by welding, the fixture frame 6-2. This frame carries aplurality of round bar members 65 arranged in parallel or grille-likefashion over the discharge opening.

In order that the semi-circular path of ad justment' travel of thewarm-air outlet fixture '52 will be closed with the exception ofthe'area of the fixture, a thin and fiexible metal strip Till, shown inFigs. 3 and 4, through an opening in which the frame 64 of the fixtureprotrudes, isslidably mounted in appropriate slots formed by the raisededges l2 of the opposing top portions of the casing halves 36 andspecially flanged metal strips it which are welded thereto. It will beunderstood that if desired the single strip withthe opening cut thereinmay be replaced by two separate strips which are respectively attachedto the two ends of the fixture frame 64. As the position of the outletfixture 42 is changed, the

fiexible strips it will follow in the grooves pro-- vided therefor inthe semi-circular top section of the casing, and at all times maintainthe pressure chamber closed with the exception of the outlet fixtureitself.

Manipulation of either of the handles 58 thus causes the outlet fixture12 to change its position in the semi-circular space between the upperportions-of the co-operating casing halves 35S and thereby changes thedirection of air discharge. To limit the travel or restrict the range ofthis adjustment, stop members, in the form of angle pieces El welded tothe side of the casing, are adapted to make contact with one of,

the strips (if! when either limit of travel is reached. To preventchattering of the ends of the flexible strip iii which protrude belowthe rim l2 of the casing halves, the welded on strips 13 may be extendeddown to an intermediate elevation as shown in Fig. 4.

It will be apparent that through the use of this improved construction,adjustment in the position of the outlet fixture 42 may be made with butlittle effort on the part of the operator, since the friction tomovement of the fixture and the flexible sealing strip attached theretomay be reduced to a low value.

Energizing current for the blower driving motor and the air heater isderived through a connection. with the lighting or other power supplycircuit established by means of a flexible cord l5 terminating in a plugconnection 76 which may be inserted into a wall or other outlet fixture.As shown, the cord enters the drier casing through a hole in the bottomof metal strip 38, in which hole an insulatitng bushing ll is placed.

The switching device at, utilized to control the operation of the drier,is illustrated as being of the so-called momentary contact type, itcompleting an energizing circuit only as long as an operating lever 8|thereof, which is maintained in the upward position shown by resilientmeans incorporated in the switch construction, is continuouslydepressed. Depression of this lever is effected by means of the foottreadle 83, which protrudes to the outside of the casing through asuitable slot 84 cut in the lower end of the spacer strip 39. Connectionbetween the treadle and switch lever is established by means of a spring85, which is of sufiicient rigidity to transmit switch-actuatingmovements. The elongating characteristic of the spring allows, withoutinjury to any of the associated mechanism, the treadle to be furtherdepressed after the switch arm 8| has reached its limit of downwardtravel.

While it will be understood that any suitable air heating unit may beutilized in the hand drier of my invention, the unit which I prefer toutilize because of economy of construction and ease of replacement, isillustrated by Figs. 6 to 9, inclusive, which heater has already beenreferred to in the explanations of the showings of the complete drierassemblage. One desirable feature of such a heater is that the heatingconductors positioned in the passage through which the air to be heatedis blown shall be uniformly distributed throughout that passage andshall not unduly obstruct the flow of air therethrough. Thus, it ispreferable to position the coils 99 of heating wire in some manner suchas is indicated by the showing of Fig. 6 which is a top or plan View ofthe improved heating unit of my invention which, as before explained, ispositioned in the cylindrical outlet passage 28 of the blower Ill.

In the construction of this heating unit, a cylindrical shell 39 isformed from sheet metal, a flat strip of which is first cut to thedesired dimensions and then bent into the circular contour of thecylinder. In this position the cooperating or overlapping edges of thesheet are spot welded or otherwise secured to each other, this junctionbeing indicated in Fig. 7 by the area of overlap 92. In the originalflat sheet are also cut two parallel oblique slots 93 and 94, each ofwhich in the assembled cylindrical shell 30 are spiral in form, as alsoindicated in Fig. 7.

The cylindrical shell having been assembled, porcelain heating wiresupports 96, a side view of one of which is shown in Fig. 8, are theninserted in the spiral slots 93 and 94, they being spaced from eachother by means of suitably slotted spacers 98 constructed of sheetmetal, an end view of one of which spacers is shown in Fig. 9. At thebottom of slot 94 and at the top of slot 93 are positioned terminalbolts 97 which secure the two ends of the coil of heater wire 96, whichcoil is progressively threaded among the specially spaced supports 96 inthe manner indicated in Fig. 6. Energizing-circuit connections with thecoil are made through the terminals 91 by means of conductors 95, whichare threaded through a porcelain bushing 99 carried by a top ring memberI08 which surrounds and is secured to the upper portion of thecylindrical shell 30 by an attachment effected by means of bolts I63, toa pair of shell ears I62.

For greater ease in assembly of the heater unit, the coil of heater wire9i may be threaded through the insulator supports 96 before theirinsertion into the slots in the cylindrical shell, in which case, thispreparatory threading operation may readily be accomplished by arrangingthe insulators which are to go in each of the two spiral slots inparallel lines on a flat surface, which lines are spaced substantiallyby the diameter of the shell, and then threading the coil of heater Wirein zig-zag fashion progressively through these supports. When spacedlyplaced in the two opposing slots, the resulting diversification of theindividual branches of the heater coil length shown in Fig. 6 willobtain, and a stream of air in being blown through the cylindrical shell30 will be uniformly and effectively heated without receiving unduephysical obstruction.

In installing the heater unit in the cylindrical discharge opening 28 ofthe blower III, it may be secured to the top rim thereof by means ofscrews I06 which are accommodated by the holes III! in the heater rimI00.

In order to obtain the desired effectiveness of a heater adapted to warmair which is'blown rapidly therethrough, it is necessary to operate theresistance wire or conductor at such a high current that should for anyreason the draft of air be discontinued, the conductor will attain suchexcessively high temperatures as to burn out. Consequently, in a deviceof the type under consideration, should for any reason the blower discontinue its operation or fail to start upon energization of the heaterunit, the unit will be burned out. To protect against damage from thiscause is one objective of the present invention.

In effecting such protection, I dispose in the energizing circuit of theheating unit, a centrifugal switch which is responsive to the speed ofthe blower shaft. This switch, which is generally indicated in theshowing of Fig. l at III), requires that the blower I6 be brought up tospeed before the heater can be energized and also serves to interruptthe heater circuit as soon as the blower speed decreases to apredetermined low value.

In the improved hand drier of my invention, I prefer to mount thisswitch directly on the shaft II 2 of the blower inside of the endbracket H4 in a manner shown in greater detail by Fig. 10. While theswitch itself may be of any suitable construction responsive to changesin speed of the shaft, the type which I prefer to utilize is that whichis more completely shown and described in United States Patent1,305,084, which issued May 27, 1919, to John B. Hansell.

As illustrated in Figs. 10, 11 and 12, this switch comprises a compositering H6, sensitive 'to changes in the centrifugal force acting thereon,mounted directly upon the blower shaft II2, a base plate H8, attached,by means of screws I2IJ, to the end bracket H4 of the blower, and acarriage I23 mounted in suitable slides on the base plate in a manner tomove in a vertical direction therein. This carriage supports, by meansof an insulating material bar I attached to the lower end thereof, apair of contact bridging members I24 and I25 which are respectivelyadapted to selectively make connection with two pairs of stationarycontact members I27 and I28 carried on an extension of insulatingmaterial I30 which is fixed to the lower end of the base plate II8.Connections with the circuits to be controlled are made by attaching theconductors, as by screws I29, to these stationary contact members.

Changes in the effective diameter of the composite ring I I6 effect anactuation of the carriage through the medium of suitable operating lugsI38 and I39 which protrude from the upper portion of the carriage andembrace the ring in the manner indicated by the side View of Fig. 10.The ring comprises, as is best indicated by Fig. 11,

aplurality of crescent-shaped'movable members 142- symmetricallypivoted, at their ends I45, to a 'baseplate I43 which is directlyattached to the shaft I I2,.each member being biased inwardly bya;.spring .I il. These-members Hi2 nest snugly witheach'other becauseofa lateral offset 'in each of them whereby the pivoted-endlies closelyadjacent to the base plate I413 and the free end overlies the adjacentmember. The free end of each of the'members is restrained in movementboth inwardly and outwardly by apin M8 working freely in a slot I50 inthe underlying member.

When the ring structure is at rest or revolving atxlow speeds, thecrescent shaped members are all. drawn inwardly by the'springs Ml, as isindicated by the showing of Fig. 11. When sufficient speed is attainedby the shaft I 42, each of the members I 32 flies outwardly under theinfluence of centrifugal force until stopped by the engagement of thepins l 58 with the ends of the slots I50. As the composite ring i itthus increases in radius, the outer edge impinges upon the upper lugl38of the contact carriage and pushes it upwardly in a uniform andgradual manner, and conversely, as the composite ring M6 decreases inradius with a decrease in speed, the inner edges of the members I42contact the lower lug H9 and push the carriage downwardly.

Through the action of a pair of bowed springs I32, embraced between aportion I33 of the carriage and extensions I36 of the base member plate,the carriage is biased, in operation of the switch, toward either limitof its movement path so that a quick and positive snap actionof thecontacts is thereby effected. Thus, when the carriage is in the lowerposition illustrated, in which stationary contact members l2? arebridged by member I24, the action of these springs is to strongly holdit in that position and thereby maintain the requisite contact pressure.Like-- Wise, when the carriage has been moved upwardly past the midpointof its movement path, the springsurge it upwardly with a constantlyincreasing force until it reaches its upper position in which thebridging member B25 is biased against the stationary members S28, thebridging member I2 3 having by this movement been separated from thestationary members lE'I.

The total range of movement of the carriage and its actuating lugs E38and i353 is made to exceed the variation in the radius ofspeed-responsive ring H5, in order that the crescent shaped members I42of this ring will not bear upon these lugs at the normal speed of theblower shaft M2, the carriage being allowed to snap free thereof, duringeach switch actuation, under the influence of bowed springs I32, intoits limiting position.

The manner in which the centrifugal switch is connected in theenergizing circuit of the heater is most clearly illustrated by thediagram of Fig. 13 from which it will be seen that a depression of thetreadle switch Bil first energizes driving motor 2il'to start the bloweris. Shortly before the blower attains normal speed, the centrifugalswitch actuates the bridging member I25 thereof upwardly to complete anenergizing circuit for the heater 90. It will thus be noted that whilean opening of. the control switch 30 deenergizes both the motor and theheater, upon a closure thereof, heater energization can be eifected onlywhile the blower is operating, a failure or discontinuance of suchoperation immediately causing the centrifugal switch to disconnect theheater from'the power source even though the motor may continue'to beenergized. Effective protec- .tion .against burnout duetoaccidentalstoppage or failure of the blower to start is in this man- :nerobtained.

For use with the alternating-current supply circuits which are at thepresent time almost universal in locations where it is desired toinstall hand driers and other comparable motor driven devices,single-phase induction motors are especially suitable and it is thistype of motor that I have illustrated as being incorporated in theimproved hand drier of my invention. In order-that such a single phasemotor may be started, it is necessary to provide it with anauxiliary-winding, shown in the diagrammatic representation ofFig. 13 atI60, physically displaced from the main winding, indicated at I62, which:main winding derives its energization directly from the supplyconductors 75 through the control switch 80. In. order toshift the phaseposition of the current which is supplied to the. auxiliary-winding I69,it is necessary to insert in the supply circuit thereof some phasedisplacing device such as a capacitor I64, and it is preferable thatthis winding be maintained energized not only during the startingoperation but also during the normal full speed running op eration-ofthe motor 20.

To increase the rapidity of starting of the motor, it is desirableinsituations of this .kind to utilize a second or starting capacitor I66 which is connected in the auxiliary winding circuit for a shortperiod aftercurrent is first supplied to the motor, the function of thisadditional capacitor being to increase the current which circulatesthrough the auxiliary winding and thereby substantially raise thestarting torque of the motor. To be most effective this increase incurrent is of such magnitude that damage from sustained overload wouldresult to the auxiliary winding I20 were the starting capacitor to bepermanently left in the energizing circuit thereof. In the complete handdrier of my invention shown in Figs. 1 and 2, these capacitors I64 and Iare shown as being mounted below the motor in the lower portion of theangle-iron frame.

To effect a removal of this starting capacitor as soon as the motor hasattained full speed, I utilize the secondset of contacts comprisingbridging member I24 and stationary members I21 of the centrifugalswitch, before described as being actuated in accordance with the speedof the driven blower IE3. When the motor and blower are at rest, thebridging member I24 completes, as isshown by the diagram of Fig. 13, anactive connection of starting capacitor I66 in the circuit through whichauxiliary winding I6!) of the motor is energized. 'As'soon as the motorand blo-wer'come up to speed, however, bridging member I2 3 is, in themanner already explained, moved upwardly to thereby interrupt'thecircuit of the starting capacitor to remove it from active service.

Although I have'shown and described'a certain specific embodiment of myinvention,'I am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be restricted exceptinsofar as is necessitated, by the prior art and by the scope of theappended claims.

I claim as my invention:

1. An electric drying device comprising, in combination, adraft-producing and air-heating mechanism, a structural frame forsupporting said mechanism, and an exterior casing adapted to surroundsaid frame and to form thereabove a pressure compartment into which saidmechanism may discharge heated air, said compartment having an openingthrough which said air may escape for direction against objects to bedried.

2. In an electrical drying device, the combination of a structuralframe, an air-blower, a driving motor therefor, and an air heatersupported by said frame, an exterior casing adapted to fit down over andbe attached to said frame above which the upper portion of the casingforms a chamber, a partition between said chamber and theframe-supported mechanism therebeneath, said partition having an openingthrough which the heated air is blown into the chamber, and saidexterior casing having in the top portion thereof an opening throughwhich said air may escape for direction against objects to be dried.

3. In an electrical drying device comprising a casing in a portion ofwhich is formed a pressure chamber provided with an air-dischargeopening of arcuate contour, the combination of an air-outlet fixture, ashaft, the ends of which protrude through the sides of the casing, foradjustably supporting the fixture in said arcuate opening, means forsealing against air escape the portions of said opening not occupied bythe fixture, and handles attached to said shaft ends to enable anoperator to change the position of the fixture in the casing opening andthereby adjust the directions of air discharge.

4. In an electrical drying device comprising a casing in a portion ofwhich is formed a pressure chamber provided with an air-dischargeopening of arcuate contour, the combination of an airoutlet fixture, ashaft, the ends of which protrude through the sides of the casing, foradjustably supporting the fixture in said arcuate opening, and means forsealing against air escape the portions of said opening not occupied bysaid fixture, said means comprising a flexible metal strip through anopening in which the said fixture extends, and grooves provided in thesides of said arcuate casing opening for slidably retaining the edges ofsaid strip.

5. In an electrical heating device comprising an air-blower, asplit-phase induction motor, having a pair of windings, for driving theblower, a source of power for the motor, a control switch, a circuit forenergizing one of said motor windings directly from the power sourceupon closure of the switch, a phase-shifting element, and a circuit forenergizing the other motor winding through said element upon closure ofthe switch, the combination of a centrifugal switch, responsive to thespeed of the blower, for interrupting said last-named circuit when theblower speed is, during a starting operation, brought up to a valueclosely approaching normal.

6. In an electrical drying device comprising a heater, a blower forforcing air through said heater, a split-phase induction motor, having apair of windings, for driving the blower, a source of power for theheater and motor, a control switch, a circuit for energizing one of saidmotor windings directly from the power source upon closure of theswitch, a phase-shifting element, a circuit for energizing the othermotor winding through said element upon closure of the switch, and acircuit through which the heater may be energized, the combination of acentrifugal switch, which is responsive to the speed of the blower,adapted to interrupt the motor-energizing circuit last named when theblower speed is brought up to a value closely approaching normal and to,at the same time, complete the said heater energizing circuit.

R. H. JORDAN.

